Stop motion mechanism for warp knitting machines



Aug. 18, 1953 T. F. SCHWANDA 2,648,962

STOP MOTION MECHANISM FOR WARP KNITTING MACHINES Filed Oct. 8, 1951 2 Sheets-Sheet 1 67 L'KTART i STOP 2 LOW ENERGY I INVENTOR.

RELAY BY ATTORNEY Aug. 18, 1953 T. F. SCHWANDA STOP MOTION MECHANISM FOR WARP KNi TT-I NG MACHINES I 2 Sheets-Sheet 2 Filed Oct. 8, 1951 FIG.5

ATTORNEY Patented Aug. 18, 1953 STOP MOTION MECHANISM FOR WARP KNITTING MACHINES Theodore F. Schwanda, Bangor, Pa., assignor to Blue Ridge Textile (30., Inc., Bangor, Pa., a corporation of rennsylvania Application October 8, 1951, Serial No. 250,215

14 Claims. 1

This invention relates to a stop motion mechanism for warp knitting machines which is responsive to defects in mesh fabrics produced on such machines.

An object of the invention has been to provide simple, reliable, and effective means for quickly stopping a machine of the character indicated whenever a hole develops in the fabric due to the breaking of one of the warp threads in the course of the knitting operation. Toward this end, the machine is equipped with a plurality of spring feeler fingers spaced at suitable intervals across the width of the machine and arranged to engage the mesh fabric along a line closely adjacent to that at which new stitches are being formed and added to the fabric. It has been found that in the warp knitting of mesh fabrics the breakage of a single thread will very quickly result in the production of a relatively large hole in the region from which the thread is being omitted. This makes it possible to hold the spoilage of fabric to a minimum by placing the spring contact fingers, in accordance with the invention, quite close to the point of stitch formation. The arrangement is such that the newly formed fabric normally holds the spring fingers out of contact with a grounded metal member, or plurality of members, in spite of the presence of small openings in the fabric incident to its mesh construction. warp threads entering into the construction breaks, which usually occurs at or near the point of stitch formation, a relatively large hole having a width of half an inch or more is quickly developed, so that one or more of the contact fingers will engage the grounded metallic part to complete a circuit for stopping the machine.

In the preferred embodiment of the invention the spring contact fingers are arranged to coopcrate with certain of the sinkers regularly employed in knitting machines of the character indicated. It is not necessary to provide a contact finger for each sinker or for each bearded. needle or guide, provided in such machines, since, as indicated, the hole which develops upon the breakage of a single thread usually spreads to a width of half an inch or more very quickly. This is due, at least in part, to the fact that each thread is carried by its guide in the course of operation of the machine across a plurality of the needles and each thread is interlocked with at least one thread on each side.

Other objects, features, and advantages of the invention will appear from the detailed description of an illustrative form of the same which However, when one of the will now be given in conjunction with the accompanying drawings, in which: u

Fig. 1 is a view, partly in vertical section an partly in elevation, of that portion of a warp knitting machine with which the feeler or detector mechanism is associated;

Fig. 2 is an electrical diagram showing a circuit arrangement which may suitably be employed in connection with the invention;

Fig. 3 is an enlarged detail view of the detector mechanism employed in Fig. 1;

Fig. 4 is a detail view, in vertical section along the line 4-4 of Fig. 5, showing means for mounting parts of the detector mechanism; and

Fig. 5 is a plan view of a portion of the detector mechanism shown in Fig. 3, parts being broken away to condense the view.

The invention has been shown as applied to a tricot fabric knitting machine of the type distributed by Aveco, Inc, of New York. It will be understood, however, that the invention is adapted for general application to warp knitting machines of various kinds which can be arranged for the production of mesh fabrics.

The warp knitting machine to which the in vention is shown applied, will contain all of the usual instrumentalities required for the production of mesh fabrics. However, only those parts which cooperate withthe novel stop motion mechanism have been illlustrated in the drawings and will be described. For further details as to the construction of the machine and its general mode of operation, reference may be had to prior patents and publications, including the patent to S. J. Thomas No. 2,464,468,

granted March 15, 1949, and the book entitled 'Iricot Fabric Design, by Thomas Johnson, published by McGraw-Hill Book Company, Inc. in 1946.

Referring now to Fig. 1, a channel member It, which forms a portion of the machine frame, carries a plurality of brackets ll that serve to support a shaft E2. 'The latter is mounted for rocking or oscillating movements about its axis, such movements being imparted by suitable connections (not shown) from cams carried by a rotary driven shaft of the machine. Arms 13 are secured to the shaft l2 and arranged to oscillate with the latter. They carry a guide bar !4 which extends substantially completely across the width of the machine and which is arranged to be shifted longitudinally on the supporting arms under control of a pattern wheel, in a manner well known in the-art. Guide bar [4 has secured to its lower edge a suitable numher of guide units l5 carrying individual thread guides it which are spaced at the distance provided between successive needles. A plurality of arms il', also secured to the shaft E2 to partake of the oscillatory movements of the latter, serve to support a guide bar l8 that extends substantially the full width of the machine and is arranged to carry at its lower edge a plurality of guide units 19 having individual thread guides 20 spaced at the distance between successive needles. Warp threads 2| are delivered from suitable spools over a fixed guide rod 22 and a movable tensioning rod 23 and from the latter are directed downwardly to the eyes of the guide elements Hi from which they are presented in proper relation to the needles and sinkers for the production of the desired fabric. Similarly, warp threads 24 are delivered from suitable spools over a fixed guide rod 25 and a tensioning rod 25 and then downwardly to the eyes of the guide elements 20 to the points of stitch formation. As will be understood, in the production of mesh fabrics threads will be omitted from certain of the guides l6 and 20 to provide the desired pattern of openings in the fabric.

Operating in timed relation with the oscillation of the shaft l2 and the step by step longitudinal reciprocation of the guide bars [4 and H] are a plurality of bearded needles 2'! assembled in suitable units 21a secured to a needle bar 28. The latter is carried by a plurality of oscillating arms 2% secured to rock shaft 28b arranged to be rocked through a suitable angle by connections (not shown) from the main drive shaft of the machine. A bearded needle 21 is provided for each of the warp threads and in a typical construction there may be 28 such needles to the inch. The number may obviously be varied to suit the requirements (i. e. gage) of the particular fabric to be produced. Also cooperating with the threads in stitch formation are a plurality of sinkers 29, equal in number and spacing to the needles. These sinkers are assembled in units which are secured to a plurality of rock arms 30 carried by a rock shaft 30a that is oscillated through a suitable angle by connections from the main drive shaft of the machine. A presser bar 3|, carried by a rock arm 32 that is oscillated in suitably timed relation to the operation of the needles, serves to close the needle beards at the appropriate times to enable the proper formation of the stitches. For further explanation as to the timing of the movements of the guide elements, bearded needles, sinkers, and presser bar, reference may be had to the book hereinabove mentioned. As a result of the coordinated action of these various devices a fabric 33 is produced at the needles and this fabric is delivered over the ends of the sinkers 29 and is then passed beneath a tubular guide 34 fixedly mounted in the frame of the machine. From the latter the fabric is delivered to suitable reeling means (not shown).

The novel hole detecting and stop motion mechanism of the present invention will now be described. Referring to Fig. 3, an angle member 35 is secured by screws 36 to the guide tube 34 beneath which the fabric is passed. This angle member extends substantially completely across the machine. Its purpose is to provide a support for certain parts to be described.

On the upper surfaces of the horizontal leg of the angle member blocks 31 are adjustably secured by means of screws 38 cooperating with elongated openings 39 in the blocks. These 4 blocks, as best indicated in Fig. 4, are formed of any suitable insulating material, such as a fiber composition, and each carries a bracket 39 which is secured to the block by one or more screws ii. The heads of the screws 4! are countersunk in the blocks 31 and are retained by the latter out of engagement with the angle member 35. This arrangement is such that the brackets 49 are insulated from the angle member 35 and thus from the frame of the machine. Each bracket has a pair of upwardly extending arms #32 between which is fitted the inner end of an arm 43. The latter is pivotally mounted on the bracket member by means of a pivot pin M which, for ease of assembly and disassembly, may be provided with flattened ends adapted, when in a vertical position, to be passed through openings 45 in the upper ends of the arms 32 and adapted, when turned into a horizontal position, to lock the pin and hence the arm 43 to the bracket. That portion of the pin which provides a journal for the arm $3 is preferably slightly larger in diameter than the circular openings in the arms 42 which receive the ends of the pin, to retain the pin against endwise movement.

Extending across the outer ends of each pair of arms 53, and secured thereto to complete a relatively rigid frame structure, is a cross bar 46, which is fastened to the ends of the arms 43 by means of countersunk screws i'i. Cross bars it are preferably arranged to extend some distance beyond each of the arms In a typical construction applied to a knitting machine capable of producing fabric having a width of 14, it has been found desirable to provide twelve arms '33 which are spaced l4 apart. The cross bars 45 are preferably about 28" long, so that they extend 6 or '7" beyond the arms :53 at each end. Six of the cross bars :5 are required in the typical installation. A slight gap is preferably provided between successive cross bars.

To the outer face of each cross bar it there is secured a series of contact members 48 formed of suitable spring material, such as stainless steel. The sheet material from which these members are formed may suitably be .016" thick. The main body of each member $8 is bent upwardly, as indicated at 58 in Fig. 3, to provide flat surface engagement with the outer face of the bar 38 to which it is secured by means of screws Prongs or fingers 5i extend outwardly from h main body of the member 63, as best illustrated in Fig. 5. These prongs or fingers suitably be about of an inch in width and about 1 in length. The spaces between successive pron may suitably be about a of an inch. Members 48 may have any suitable overall width, but it has been found desirable to make them about 5%- of an inch wide. Accordingly, on each cross bar 45 there will be mounted 14 of such members which, in the typical example indicated, will Provide contact fingers or prongs having their longitudinal axes spaced /4 of an inch apart. Each of the prongs is curved at its outer end as best shown in Fig. 3. The downward curvature at 52 may suitably be along a radius of of an inch and the reverse, upward curvature may suitably be along a similar radius. The free upper end 5 2 of the curved portion of the prong is preferably a slight distance above the plane of the main body of the prong, e. g. about 5% of an inch. The convex under surface of the curved portions 53 of the several prongs are arranged to rest upon the upper surfaces of the end Dortions of the sinkers 29. It will be understood that in the operation of the machine, as the fabric is being produced, the latter will pass between the under surfaces of the prongs 5| and the sinkers 29, so that metal to metal contact is eliminated. Only a relatively light pressure is exerted between each prong 5i and its cooperating sinker, since the total force applied to all of the sinkers which are engaged by a contact prong is only that due to the gravity force acting upon the arms 43 and cross bars 46 and tending to rock them downwardly. The springs are in contact with successive points on the cloth for only a Very short time so that no wear of the fabric results from the continual oscillation of the sinkers beneath the prongs. It will be understood that the extent of the oscillation of the sinkers is such that they will never pass completely from beneath the rounded portions 53 of the prongs.

The width of each prong or finger 5| is such that its rounded portion 53 will not pass through the normal openings in the mesh fabric. However, when one of the warp threads 2| or 2% breaks in the course of the operation of the machine and a relatively large hole of the character above indicated develops, one or more of the prongs 5i will pass through the fabric and come in direct engagement with the related sinker. By virtue of the mounting of the sinkers these are all grounded to the frame of the machine.

In accordance with the present invention, the

engagement of one of the fingers 5| with a sinker will serve to complete a circuit which will then bring about the stoppage of the machine.

Since a fire hazard would be involved if any substantial amount of current were passed through the circuit closed in the manner indicated, due to possible sparking, it is important that a current of low voltage and amperage be employed. Accordingly, to enable the operation of the necessary switches or circuit breaking means to bring about stoppage of the machine, it is desirable to employ a low energy relay in the detector circuit which is closed by the engagement of a contact finger with the grounded sinker. Any suitable arrangement of this character may be employed. One appropriate form is illustrated schematically in Fig. 2 in relation to a three phase motor system. It will be understood that similar arrangements may be provided in relation to systems making use of single phase, double phase or direct current motors. In Fig. 2 the arrow 55 symbolizes the contact finger 5! which is engaged with the grounded sinker. This serves to close a circuit to the ground terminal indicated at 56, through appropriate circuits and devices within a low energy relay unit 51. The latter may suitably be of the Westinghouse electronic type described in Instruction Book 18-710-1, published by Westinghouse Electric Corporation in 1949. Reference should particularly be had to the diagrams appearing on prints designated l9-D-6029 and 19-D-7915. It wil1 be understood that the line extending from the relay unit to the contact 55 is in fact a wire connecting the unit with an appropriate point on one of the arms 43 or cross bars 46. All of these are appropriately interconnected electrically. The line extending from unit 51 to ground simply a wire from the unit to a convenient point on the machine frame.

The arrangement is such that a work relay 58 is normally energized when the circuit is broken or is open at the contact 55. However, when the circuit is closed at the contact 55, the work relay is deenergized or falls out of operation so that a spring or springs will serve to open switchv contacts 59, 60 and 6! in the three-phase, alternating current lines 62, 63 and 64, respectively.- The supply of power to the motor 65, which is arranged to drive the knitting machine will then be cut off. Such power may be cut off manually, if desired, by operation of the stop switch 66. In the illustrative arrangement, as disclosed in greater detail in the Westinghouse Instruction Book, mentioned above, the current for the operation of the low energy relay, including that for the circuit closed by the contact 55, may be supplied from the lines 62 and 64 upon the operation of the starting switch 61. Any suitable means, such as a separate manual switch (not shown) may be employed for preventing the automaticstopping of the machine by the closing of a cir-- cuit through one or more of the detector fingers 5! until the operation of the machine has pro-- gressed suliiciently to provide a line of fabric be-' tween the fingers 5| and the related sinkers 29. If desired, the frames 43, 46 may simply'be raised for a few seconds when the machine is started up, to accomplish this purpose.

While an illustrative form of the invention has been disclosed in considerable detail, it will be understood that various changes may be made, in the construction and arrangement of the several parts and devices employed, within the scope of the appended claims. mensions indicated above are illustrative of a preferred embodiment of the invention and may be varied to best suit the requirements of a particular installation.

What I claim is:

1. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means ad- 'acent the line of stitch formation and in the path of advance of the fabric, feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, an electric circuit arranged tobe completed upon engagement of said feeler means with said grounded means, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized opening in said fabric for arresting the operation of said machine.

2. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric, said stitch forming means including a plurality of sinkers, said sinkers being grounded to the framework of the machine, the combination of yielding feeler means arranged to engage the fabric at a plurality of spaced points and servin to urge the same against said sinkers, an electric circuit arranged to be completed upon engagement of said feeler means with one of said sinkers, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with one of said sinkers through an opening in said fabric for stopping said machine.

3. In a warp knitting-machine having thread guides and stitch forming means arranged to produce mesh fabric, said stitch forming means including a plurality of sinkers, said sinkers being grounded to the framework of the machine, the combination of yielding feeler means arranged to engage the fabric at a plurality of spaced points and serving to urge the same against said sinkers, an electric circuit arranged to be com- The specific di-' pleted upon engagement of said feeler means with one of said sinkers, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with one of said sinkers through an opening in said fabric for stopping said machine, said electrically operated means including a low energy relay responsive to the closing of said electric circuit through said feeler means.

4. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancin the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, said feeler means comprising a plurality of spaced spring fingers yieldingly urged against said fabric, an electric circuit arranged to be completed upon engagement of one of said fingers with said grounded means, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized opening in said fabric for arresting the operation of said machine.

5. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adj acent the line of stitch formation and in the path of advance of the fabric, a normally open electric circuit including said grounded means and feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, said feeler means comprising a plurality of spaced spring fingers yieldingly urged against said fabric, each of said spring fingers having a rounded fabric engaging portion arranged to engage said fabric, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized opening in said fabric for arresting the operation of said machine.

6. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, an electric circuit including said grounded means and feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, said feeler means comprising a pivotally mounted support and a plurality of resilient fingers carried by said support and urged thereby into engagement with said grounded means, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized openin in said fabric for arresting the operation of said machine.

7. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, said feeler means comprising a pivotally mount pp rt a d a p r it of esilie t fingers carried by said support and urged thereby into engagement with said grounded means, an electric circuit arranged to be completed upon engagement of one of said fingers with said grounded means, the fabric engaging portions of said fingers being rounded and of such dimension as not to pass through the normal openings in said mesh fabric, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized opening in said fabric for arresting the operation of said machine.

8. Ina warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, a pivotally mounted frame extending substantially horizontally toward said grounded means, a plurality of spaced spring fingers carried by said frame and extending over said grounded means, said fingers being urged yieldingly against the fabric passing over said grounded means, an electric circuit arranged to be closed by engagement of any-one of said fingers with said grounded means, and means responsive to the closing of said circuit for stopping the operation of said machine.

9. In a warping knitting machine havingthread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, said stitch forming means comprising a plurality of closely spaced bearded needles, the combination of grounded means adjacent the line of stitch formation, and in the path of advance of the fabric, feeler means yieldingly engaging said fabric at a plurality of spaced points in the region of said grounded means, said feeler means being arranged to engage said fabric at points beyond said needles at points spaced substantially greater than the spacing of said needles, an electric circuit arranged to be com pleted upon engagement of said feeler means with said grounded means, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with said grounded means through an oversized opening in said fabric for arresting the operation of said machine.

10. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric, said stitch forming means including a plurality of closely spaced sinkers, said sinkers being grounded to the framework of the machine, the combination of yielding feeler means arranged to engage the fabric at a plurality of spaced points and serving to urge the same against said sinkers, said feeler means comprising a plurality of fingers arranged to cooperate with only certain of said sinkers spaced at a greater distance than successive sinlrers, an electric circuit arranged to be closed upon engagement of one of said fingers with one of said sinkers, and electrically operated means responsive to the closing of said electric circuit upon engagement of said feeler means with one of said sinkers through an opening in said fabric for stopping said machine.

11. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, a pivotally mounted 12. In a warp knitting machine having thread I guides and stitch forming means arranged to produce mesh fabric and means for advancing the I fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, a pivotally mounted frame extending substantially horizontally toward said grounded means, a plurality of resilient fingers projecting from the end of said frame and extending over said grounded means, said fingers urging the fabric yieldingly at spaced points against said grounded means, said fingers being about 3% of an inch in width and having their axes spaced about A; of an inch apart, an electric circuit arranged to be closed by engagement of any one of said fingers with said grounded means, and means responsive to the closing of said circuit for stopping the operation of said machine.

13. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, a pivotally mounted frame extending substantially horizontally toward said grounded means, a plurality of resilient fingers projecting from the end of said frame and extending over said grounded means, said fingers urging the fabric yieldingly at spaced points against said grounded means, said fingers being about 3% of an inch in width and having their axes spaced about A; of an inch apart, the portions of said fingers which are arranged to engage said grounded means being curved in a longitudinal direction about an arc having a radius of about of an inch, an electric circuit arranged to be closed by engagement of any one of said fingers with said grounded means, and means responsive to the closing of said circuit for stopping the operation of said machine.

14. In a warp knitting machine having thread guides and stitch forming means arranged to produce mesh fabric and means for advancing the fabric, the combination of grounded means adjacent the line of stitch formation and in the path of advance of the fabric, a pivotally mounted frame extending substantially horizontally toward said grounded means, a plurality of resilient fingers projecting from the end of said frame and extending over said grounded means, said fingers urging the fabric yieldingly at spaced points against said grounded means, an electric circuit arranged to be closed by engagement of any one of said fingers with said grounded means, and means responsive to the closing of said circuit for stopping the operation of said machine.

THEODORE F. SCHWANDA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,421,092 Thomas May 27, 1947 2,493,557 Tanguay Jan. 3, 1950 

